The last decade has seen many advances in the fields of microtechnology and nanotechnology. One of the challenges created by these advances is developing practical uses for discovered scientific phenomena.
A few published reports of attempts to integrate nano- with microtechnology for biomolecular or viral detection have been described [W. Liu et al., Lab Chip, 5, 1327 (2005); K. Yun, D. Lee, H. Kim, E. Yoon, Meas. Sci. Technol., 17, 3178 (2006); J. Steigert et al., JALA, 10, 331 (2005)]. In these studies, the researchers used a combination of nanoparticles, microbeads, and microfluidics for detection. In all cases, the detection sensitivity was lower than desirable for a productive, commercial product. Furthermore, the analysis was not conducted in serum, which could decrease sensitivity because of interference from blood components [E. D. Goluch et al., Lab Chip, 6, 1293 (2006)].
Similarly, bio-barcodes using gold nanoparticles have been demonstrated for applications in genomic or proteomic diagnostics [J. Tate, G. Ward, Clin. Biochem. Rev., 25, 105 (2004); S. I. Stoeva, J. Lee, C. S. Thaxton, C. A. Mirkin, Angew. Chem. Int. Ed., 45, 3303 (2006); P. Mitchell, Nat. Biotech., 20, 225 (2002)]). In these methods, the detection strategy requires multiple steps to achieve assay detection as well as amplification to achieve good sensitivity. Thus, there is a need for a detection system that only requires a few steps and can achieve a reasonably high level of sensitivity.
Published United States Patent Application No. US2007/0020779 of Stavis et al. discloses a method of detecting quantum dots conjugates in a sub-micrometer fluidic channel. The cross-sectional size of the channels used in Stavis is on the order of 500 nm and the detected conjugates on the order of 5-10 nm. Furthermore, in order to achieve single conjugate detection, the concentration of the sample was reduced to the femtomolar level, increasing the difficulty of sample preparation and the limits on the detection system. An alternative and more efficient system and method of single conjugate detection, ideally for use with more easily handled micro-scale molecules, is needed.
Objects of this invention are preferably accomplished, but may not be necessarily as described, nor is it necessary for all objects to be accomplished by a single embodiment of the invention. Additional objects may be accomplished that are not listed herein.
It is an object of this invention to enable multiplexed detection of target molecules of one or more target types by irradiating and detecting fluorescent emission from a single-file stream of test molecules.
It is an object of this invention to enable testing of biological samples for infectious diseases. It is a further object to enable testing of specific biological samples of blood, serum, sputum and/or urine.
It is an object of this invention to enable multiplexed testing for infectious diseases in biological samples. It is a further object to enable multiplexed testing for Hepatitis B, Hepatitis C and HIV in any combination.
It is an object of this invention to provide an improved microfluidic channel structure that facilitates flow through the channels.
It is an object of this invention to provide a fixed-wavelength EMF radiation device, such as a 488 nm laser, as the irradiation device in a test system such that the incident EMF radiation and emitted fluorescence from the target molecule can travel along the same optical path prior to the emitted fluorescence entering the detection device.
It is an object of this invention to partially or completely fulfill one or more of the above-mentioned objects and to mitigate and/or ameliorate any disadvantages of the prior art, regardless of whether any such disadvantages are described herein.